Junction field-effect transistors (FETs) are semiconductor devices which exhibit low noise and high input impedance. As a result, junction FETs (JFETs) can be useful in such devices as low noise ring oscillators, as well as memory devices. The properties of junction FETs may also be useful for implementing operational amplifiers with high input-impedance and/or very high current-gain. Operational amplifiers can be viewed as essential building blocks of analog electronics. Low noise has also been deemed to be a critical factor in analog electronics, particularly in high precision computation.
Junction FETs can also be used to implement negative differential resistance (NDR) using what has been referred to as a “lambda-diode” structure. NDRs have many applications in analog electronics including, but not necessarily limited to, low-noise/high-gain amplifiers, low-noise buffers, voltage-controlled oscillators and bistable circuits such as Schmidt-triggers. Unlike conventional cascode amplifiers, NDR-based amplifiers do not require large overdrive voltages. NDR elements are also of interest in digital electronics.
Emerging mobile and Internet of Things (IoT) applications require low power devices. Larger battery driven IoT devices can also benefit from low noise and high input impedance while running on low voltage for certain applications.
There is also a renewed interest in the analog implementation of neural networks, which may be highly beneficial given efficient/low-power implementation of cognitive tasks such as pattern recognition and natural language processing.
There is a need, therefore, for an improved junction FET that is area efficient and operates with a relatively low voltage.